On this day October 6, 1973

Egypt, under the leadership of President Anwar Sadat, launched Operation Badr in co-ordination with Syria, respectively crossed the cease-fire lines in the Sinai and the Golan Heights, which had been captured and occupied by Israel since the 1967 Six-Day War.

1973 Golda Meir, Pat and Richard Nixon

The War was fought from October 6 to October 26, 1973, began with a joint surprise attack on Yom Kippur, the holiest day in Judaism.

Attacking across the Suez Canal, the Egyptians were successful during the first four days of the war, following which the front settled into a stalemate.

After a disastrous Egyptian attempt to renew the offensive, the Israelis counterattacked, striking at the seam between two Egyptian armies. In over a week of heavy fighting, the Israelis crossed the Suez Canal (where the old ceasefire line had been), and eventually cut off elements of the Egyptian Third Army after a United Nations cease-fire had failed.

The war had far-reaching implications for many nations. The Arab World, which had been humiliated by the lopsided defeat of the Egyptian-Syrian-Jordanian alliance during the Six-Day War, felt psychologically vindicated by its string of victories early in the conflict. This vindication paved the way for the peace process that followed, as well as liberalizations such as Egypt’s infitah policy.

The Camp David Accords, which came soon after, led to normalized relations between Egypt and Israel—the first time any Arab country had recognized the Israeli state. Egypt, which had already been drifting away from the Soviet Union, then left the Soviet sphere of influence entirely.

In response to U.S. support of Israel, the Arab members of OPEC, led by Saudi Arabia, decided to reduce oil production by 5% per month on October 17. On October 19, President Nixon authorized a major allocation of arms supplies and $2.2 billion in appropriations for Israel. In response, Saudi Arabia declared an embargo against the United States, later joined by other oil exporters and extended against the Netherlands and other states, starting the 1973 energy crisis.